These studies are designed to clarify the immunologic mechanisms that can lead to ocular and specifically corneal pathology. The experimental models to be employed involve a local in vivo graft-versus-host reaction on the corneal endothelium and studies in vitro tissue culture of the action of virus-specific lymphocytes on infected corneal endothelial cells. Studies of corneal wound-healing will explore the possibility that the polypeptide secretory component of immunoglobulin A may serve as a physiologic marker of conjunctival-corneal epithelial metaplasia. In addition, we will examine the significance of the production of corneal endothelial multinucleated giant cells and polyploid cells which are found during endothelial repair. Attempts will be made to reconstitute the endothelial layer in corneal organ culture, employing endothelium from other sources. These corneas will then be used for keratoplasty to study donor-recipient histocompatibility relationships and the mechanism of corneal graft rejection.